Vince
i used to build dune/desert truggies (front/midship engine with individual transmission & quickchange rear ends ....not trans-axle buggies)
one of the biggest advantages of my cars was the ability to use full manual planetary transmissions (usually highly modified TH350/400)
we used sequential shifters that you could "slap" up and down in a split second (safety gated to avoid accidental shifting into reverse & park)
the manual valve body was modified to allow engine braking ("drag race" manual VB`s usually dont have/need that feature)
however, we still used a torque converter, but a very "tight" one with very low stall speed (near no slip)
this allowed us to skip the clutch and gave us the ability to shift under full throttle without braking our necks
in sand (high rolling resistance!) the advantage of full throttle shifts is HUGE
power flow is never interrupted ... rpm drop is very minimal... turbos dont loose boost
downside was that we had only 3 gears
(but the final drive ratio tune-ability of the quickchange rearends helped a lot to adjust the gear ratios to different driving areas)
one of my cars has an all aluminum 572 cid twin turbo / intercooled dry sump Brodix engine (well over 1000 hp at the rear tires
)
with a "one off" TH400/ Alison hybrid transmission,
the "mortar shell" like sound of the upshifts under full throttle in that car is something that i will never forget
anyway .... what i try to say is imho i dont really see an advantage of using a clutch
a "tight/low stall" TC will eliminate the slushbox feeling but still gives you the advantage of "cushioned" shifts